입내 분산형 Al₂O₃/Ag 나노복합체의 제조와 특성

천승호,한인섭,히데오 아와지,Cheon, Sung-Ho,Han, In-Sub,Awaji, Hideo 한국세라믹학회 2007 한국세라믹학회지 Vol.44 No.4

Alumina/silver ($Al_2O_3/Ag$) nanocomposites with Ag content up to 9 vol% were prepared from nanopowder by soaking method using ${\gamma}-Al_2O_3$ of needle type and spark plasma sintering (SPS). The mechanical properties of specimens were investigated three-point flexural strength and toughness as a function of the Ag contents. The maximum flexural strength of the alumina/silver nanocomposite was 850 MPa for the 1 vol% composite, and also higher than monolith alumina as about 800 MPa at 3, 5, and 7 vol% Ag contents. Fracture toughness by single edged V-notch beam (SEVNB) was $4.05MPa{\cdot}m^{1/2}$ for the 3 vol% composite and maintained about $4.00MPa{\cdot}m^{1/2}$ at 5, and 7 vol% Ag content. Microstructure of fracture surface for each fracture specimens was observed. Due to the inhibition effect of alumina grain growth, the average grain size of nanocomposites depends on the content of Ag nano particles. The fracture morphology of nanocomposite with dislocation (sub-grain boundary) by silver nano-particles of second phases in the alumina matrix also showed transgranular fracture-mode compare with intergranular of monolith alumina. Thermal conductivity of specimens at room temperature was about 40 W/mK for the 1 vol% Ag content.

초고속 InGaAsP광 변조기 설계에 관한 연구

한상국,한섭 연세대학교 산업기술연구소 1997 논문집 Vol.29 No.1

최근 광 증폭기의 개발로 광통신에서 광전력의 크기는 조절이 가능하나 전송속도를 크게하기 위해서는 광 변조시 발생하는 처핑을 최소화 해야 한다. 본 논문에서는 10Gbit/s급 광통신 시스템을 위한 광 흡수 변조기를 설계하고 그 특성을 고찰하였다. 흡수층 구조는 대역폭, 구동전력 대 소광비 효율, 그리고 편광손실을 모두 고려하여 결정하여야 한다. 1.46㎛ 밴드갭 파장을 갖는 흡수층의 경우 10dB/V이상의 소광비와 10GHz이상의 대역폭, 그리고 20dB 소광비에서 1.75dB이하의 편광손실을 얻을 수 있었다. Recently, the development of optical amplifier allows the optical power control in optical communication system. But still the minimum chirped lightwave signals during optical modulation are required for high data rate optical transmission systems. This paper describes the design of electroabsorption modulators for 10Gbit/s optical communication systems, and analyzes its operating characteristics. The bandwidth, the extinction ratio per unit voltage and the polarization loss were considered simultaneously to obtain the optimum absorption layer structure. The modulation efficiency over 10dB/V, the bandwidth over 10GHz and the polarization loss of 1.75dB at 20dB extinction were achieved with an absorption layer of 1.46㎛ bandgap.

대전시 유통 과실류의 농약 잔류 실태 및 위해성 평가

한국탁,박혜진,이규승,김일중,김규섭,조성민 한국환경농학회 2002 한국환경농학회지 Vol.21 No.4

대전시 노은 도매 시장에 서 채취한 과실류와 6종의 농약잔류량을 조사한 후 이에 대한 위해성 평가를 실시하였다. 전체 120건 분석시료 중 70.8%가 농약 성분이 검출되었고 그중 1.67%가 잔류허용기준치을 초과하여 검출되었다. 검출 비율이 높은 시료는 사과, 복숭아, 포도 등이었다. 검출된 성분에서 살충제는 유기인계, 합성 pyrethroid계, 유기염소계가 비슷한 비율로 검출되었고, 살균제에서는 특히 procymidone(dicarboximide계)과 chlorothalonil(유기염소계)의 검출비율이 높았다. 검출빈도가 높은 성분은 chlorothalonil, chlorpyrifos, fenvalerate, procymidone, deltamethrin, EPN의 순이었다. 위해성을 평가하기 위해서 각 농작물에 대한 농약의 추정섭취량과 ADI를 비교한 결과, 추정섭취량의 비율이 1.221%이하로 나타나 그 영향이 매우 낮은 것으로 판단되었다. 이것은 농약 잔류 허용기준치를 초과한 농작물인 복숭아에서 chlorothalonil, EPN에 대해서도 동일한 결과를 나타내었다. Pesticide residues in some fruits collected at Noeun wholesale market, Daejeon were surveyed and assessed its risk. In 120 samples, the detection rate of pesticide was 70.8% and the rate exceed MRL was 1.67%. Highly detection rate of commodities was apple, peach and grape. Organophosphorus, organochlorine and pyrethroid insecticide were found with similar rate relatively, but most of fungicides were procymidone(dicarboximides) and chlorothalonil(organochlorine). The order of detected pesticide were chlorothalonil, chlorpyrifos, fenvalerate, procymidone, deltamethrin and EPN. In order to assess risk, estimated intake amount of each pesticide was compared to ADI. Although some peach were exceed MRL, the total amount and uptake pesticides was less than 1.22% comparing to ADI.

Lactobacillus casei YIT9018로부터 분리, 정제한 Whole Peptidoglycan의 In Vitro 항종양활성

金昌漢,李明燮,高時煥,朴相瑨,朴圭炫,白永振 건국대학교 생명과학연구원 1995 생명과학지 Vol.2 No.1995

김밥의 미생물적 안전성과 관능평가

이명섭,김창한,박상진 건국대학교 동물자원연구센터 1998 動物資源硏究誌 Vol.19 No.-

시중에 유통 중인 도시락 김밥 4종류를 수거하여 미생물적 안정성과 관능평가를 실시하였다. 시료가 판매점에 도착 직후와 유통시간 경과 후에 조사한 일반생균수는 각각 1.7 X 10²∼8.9 X 10²cfu/g과 5.8 X 10²∼ 3.6 X 10³cfu/g 범위에 있었다. Escherichia coli, Salmonella, Staphylococcus aureus 및 Vibrio는 모든 시료에서 검출되지 않았다. 관능검사에 있어서 4개 시료 모두에서 판매점 도착 직후와 유통시간 경과 후 시료에서 조직감과 종합적 기호도에서 약간의 차이를 나타내었는데 이러한 결과는 냉장보관에서 유래되는 밥알의 경화에 의한 것으로 사료되었다. Microbial safety and sensory evaluation were carried for four kinds of ready-made Kimbap. Total viable cells were from 1.7 X 10²to 8.9 X 10² cfu/g just after delivered to a convenience store. After storage for 7 hours at 10℃ refrigerator, total viable cells were slightly increased with range from 5.8 X 10² to 3.6 X 10³cfu/g. No coliform bacteria, Salmonella, Staphylococci, and Vibrio were detected from the samples tested. In sensory evaluation of the samples, a little change in texture and acceptability were occurred, which was mainly from the hardening of steamed-rice during storage at refrigerator.

융기 및 테일보이드 폐합효과를 고려한 실드터널의 거동해석

진치섭,한상중 釜山大學校生産技術硏究所` 1998 生産技術硏究所論文集 Vol.54 No.-

실드 터널공법은 연약지반이나 붕괴성 지반에 매우 유리한 터널공법이므로 날로 그 사용이 증대되고 있다. 실드터널을 유한요소법으로 해석할 경우에는 초기 융기와 테일 보이드 폐합에 의한 효과를 고려하여야 한다. 본 연구에서는 Mohr-Coulomb 항복기준을 적용하여 개발한 2차원 탄·점소성 유한요소 프로그램을 이용하여 실드터널의 융기 및 테일보이드 폐합효과를 고려한 해석을 하였으며, 지반교란에 따른 장기거동은 고려하지 않았다. 해석 대상은 N-2 터널로서 실드 막장에서의 압력이 다른 2개의 계측라인에 대하여 계측치와 비교하였다. 융기, 테일보이드 폐합 및 세그먼트 설치 후의 지반거동에 대한 해석결과가 계측치와 유사한 형상을 나타내고 있으므로, 막장압력의 변화에 따른 융기조절로 지반거동에 대한 시공관리를 할 수 있을 것이다. The use of shield is increasing day by day, because it is advantageous tunneling method to the soft and collapsible ground. In case of analyzing shieldfunnel by FEM, behavior of ground due to initial heaving and tail void closure must be considered. In this paper 2 dimensional elasto·viscoplastic finite element analysis program was made using Mohr-Coulomb yield criterion for the shield tunnel considering effects of initial heaving and tail void closure, but not considered long term behavior of ground due to disturbance. The object of analysis was N-2 Tunnel, the numerical values were compared with the measured values that the bulkhead earth pressure is different in 2 instrumentation lines. Since the results of analysis are similar to the measured behavior of ground for heaving, tail void closure and liner installation, therefore the control of construction for the ground behavior can be made by the control of heaving due to variation of bulkhead earth pressure.

Lactobacillus casei YIT 9018로부터 분리·정제한 Cell Wall Skeleton의 In Vitro 항종양 활성

金昌漢,李明燮,高時煥,朴相瑨,高明秀,白永振 건국대학교 1995 學術誌 Vol.39 No.2

In vitro antitumor activity of cell wall skeleton(CWS) purified from Lactobacillus casei YIT 9018 was examined by clonogenic assay. CWS had antitumor activity against six human tumor cell lines and three mouse tumor cell lines. Antitumor activity of CWS against human tumor cell lines such as A-427, SKMES-1, SF-188, FARROW, RAJI and HEP-2 was observed at 300,800,400,700,900 and 1,000μg/ml concentration, respectively. Antitumor activity of CWS against mouse tumor cell lines such as 3LL, S-180 and P388 was observed at 50,500 and 900μg/ml concentration, respectively. Key words : Lactobacillus casei YIT 9018, Cell Wall Skeleton, Antitumor Activity, Clonogenic Assay

신경망과 TDL 구조에 의한 신호예측

이호섭,김태원,최한고,이상재 金烏工科大學校 1997 論文集 Vol.18 No.-

Neural networks have the potential in the adaptive prediction of nonstationary time series by virtue of the distributed nonlinearities and the learnings ability. This paper describes the adaptive prediction using the cascade combination of nonlinear and linear modulus. Recurrent neural networks (RNNs) and conventional tapped-delay-line (TDL) filter are used as the nonlinear and linear models respectively. For the relative comparison of prediction performance, the proposed predictor was compared with the RNN-based predictor. Simulation results show that the proposed predictor with smaller number of system weights performs better than the RNN-based predictor. We also found that it was well applicable for the prediction of the time series which contains large variations of signal amplitude.

Lactobacillus casei AHU 1055 및 Lactobacillus acidophilus JAM 1043의 凍結乾燥와 生存率에 關한 硏究

金昌漢,金明浩,朴芝賢,李明燮,朴相瑨 건국대학교 동물자원연구센터 1992 動物資源硏究誌 Vol.17 No.-

In order to find the most suitable conditions of freeze-drying for the long term preservation of lacto-bacillus casei AHU 1055 and Lactobacillus acidophilus JAM 1043, the growth phase, the cryoprotection medium and inoculum size have been studied. The results obtained in this study are summerized as follows : 1. L. casei AHU 1055 and L.acidophilus JAM 1043 reached to stationary phase after incubating at 37˚C for 16hrs and 12hrs in MRS broth, respectively. 2. The highest viability of each strains was obtained in 11% skim-milk for L. casei AHU 1055 and 9% skim-milk for L. acidophilus JAM 1043 as basic cryoprotection medium. 3. The complex medium contained 11% skim milk powder, 2.5% arginine and 3% glucose was the best suspending midium for freeze-drying of L. casei AHU 1055, and the medium contained 9% skim milk powder, 7% glycerol, 9% lactose, 0.5% arginine was the best suspending medium for freeze-drying of L. acidophilus JAM 1043. 4. The strong positive correlation was found between inoculum size and the survival rate in both strains. 5. When the tested strains were cultured and freeze-dried under the best optimal conditions, the survival rates of freeze- dried L. casei AHU 1055 and L. acidophilus JAM 1043 were 85.8% and 84.0%, respectively.

인지기능과 사건관계 전위

이성훈,이종섭,한은선,유계준 大韓神經精神醫學會 1990 신경정신의학 Vol.29 No.4

Event related potential(ERP) were measured in thirty one normal controls(32.9±6.3 in average age), while two kinds of stimuli, frequent and infrequent stimuli were given with an instruction(for counting infrequent stimuli), without an instruction. The amplitudes on N1, P2, P3 were significantly higher with infrequent stimuli than with frequent stimuli in ignoring condition. In instructed condition, the significantly higher amplitudes in P1, N1, P3 components were noted with infrequent stimuli than with frequent stimuli. The amplitude of P3 increased most prominently in an attending condition comparing to an ignoring condition. Good performers of this task showed significantly higher amplitudes in N1 and P3 than bad performers.